CODEWITHSUNDEEP
javascriptarraysvue.jsindexof
brunouno
brunouno

Reputation: 595

Vue JS - indexOf array is not a function

I'm trying to check if a number is present in an array (which I've done a thousand times before using .indexOf()) but I seem to be missing something now.

Vue method

showSeat(seat) {
    if( !this.selectedSeats.length ) { 
        this.selectedSeats.push(seat)
    } else {
        let index = this.selectedSeats.indexOf(seat)
        ( index >= 0 ) ? this.selectedSeats.splice(index,1) : this.selectedSeats.push(seat)
    }
}

Initially, this.selectedSeats is equal to [], and the first condition runs perfectly. However, when I try to add another seat, I get [Vue warn]: Error in event handler for "showSeat": "TypeError: this.selectedSeats.indexOf(...) is not a function". What am I missing?

Upvotes: 0

Views: 6563

Answers (1)

David784
David784

Reputation: 7464

This is one of those rare cases in JavaScript where leaving off a semicolon can cause huge problems. These two lines are being evaluated as a single expression:

 let index = this.selectedSeats.indexOf(seat)
 ( index >= 0 ) ? this.selectedSeats.splice(index,1) : this.selectedSeats.push(seat)

It's trying to execute this.selectedSeats.indexOf(seat)(index>=0)

Add a semicolon at the end of your indexOf(seat); and you should be fine.

Upvotes: 4

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